I have landscape solar panel which is used for on off switch. Typical solar panel model has didoes internal resistances back resistances. I used general purpose transistor but its not working as expected with transistor as switch with solar panel. What is good transistor model name, mosfet bipolar npn pnp etc to use as switch with solar panel?

 

I have landscape solar panel which is used for on off switch. Typical solar panel model has didoes internal resistances back resistances. I used general purpose transistor but its not working as expected with transistor as switch with solar panel. What is good transistor model name, mosfet bipolar npn pnp etc to use as switch with solar panel?

Show us your circuit with the parts you are using and include the power of the solar panel(s) being used.

 

While at it, how much voltage do you want to switch,
how much current will you be switching, and
what is the source of and nature of the switch signal?

 

Show us your circuit with the parts you are using and include the power of the solar panel(s) being used.

How do I know power of dolar oanel? It came factory assembled into landscape light their is nothing indicating solar panel power

 

How do I know power of dolar oanel? It came factory assembled into landscape light their is nothing indicating solar panel power

You measure it. Do you have a multimeter?

Also, be aware, that a single transistor does not act like an on/off switch. It also allows everything in between. You likely need a more complicated circuit (Schmitt trigger) if you want only on or off.

Still waiting for the circuit you tried. We are not mind readers here.